Apparatus for making piston rings



' Dec. s', 19254. 1.565.220

E. H. WEHLANN APPARATUS FOR MAKING PISTONRINGS Filed Dc. 8. 1919Patented Dec. 8, i925.

UNITED STATES PATENT www EDWARD H. WEHLANN, OF DETROIT, MICHIGAN,ASSIGNOR T PACKARD MOTOR CAR. COMPANY, F DETROIT, MICHGAN, A CORPORATION0F MICHIGAN.

APPARATUS FOR MAKING PISTON RINGS.

Application led December 8, 1919. Serial No. 343,304.

.To all whom t may concer/a.'

Be it known that I, EDWARD H. "WEH- LANN, a citizen of the UnitedStates, and resident of Detroit, lWayne County, State e of Michigan,have invented certain new and useful Improvements in Apparatus forMaking Piston Rings, of which the following is a specification.

This invention relates to processes and apparatus for making pistonrings.

The finishing or grinding of piston rings has heretofore been subject toconsiderable difficulty since the rings after being ground do notaccurately fit the walls of the c linder and, therefore, cause a leakageof t e gas within. the cylinder past the piston. 1t has been customaryin the finishing of piston rings to place a series of rings inside of acylindrical sleeve, the sleeve being of the correct diameter to hold therings in contracted position. A clamp is then placed within the sleeveand the rings are rigidly held between its two clamping flanges. Theclamp and the rings held thereby are then withdrawn from the sleeve andthe outer peripheral surfaces of the rings are ground to size. Ringstreated in the manner just described when placed on the piston and inthe cylinder are found to have i high spots located near the split endsof the ring and also at the opposite side 'of the ring. These high spotscontact with the walls of the cylinder but between the high spots areformed low spots which cause leakage. The high spots which result fromthe process of manufacture just described are caused by the distortionof the rings, as they are forced into the sleeve. from the shape theywould naturally assume if the rings were contracted by means of aflexible or nonrigid band.

The present invention has for its object to produce a ring which is notsubject to the objections above outlined and a ring that will bearevenly at all points against the inner wall of the cylinder.

Further objects will appear as the description proceeds.

The object above outlined is attained in the present instance bycontracting the ring without distorting it and by grinding the ring socontracted to a true cylindrical shape. In carrying out the inventionone of the rings to be finished is contracted by means 4of Ja flexible,member which encircles the ring and gradually contracts the ring untilthe split between the ends of the ring closed. l/Vhen the ring has beenso contracted it is retained in this position by some suitable means.

The ring so contracted may be placed in a clamp and ground to the propersize, or, if it is desired to finish a plurality of rings, thecontracted ring may be used asa pattern or templet by which to shape theinner wall of a sleeve which may be used for holding a series of ringsin contracted condition. A fter the sleeve has been made and the ringshave been placed therein, a clamp is inserted in the sleeve and thecontracted rings are clamped together. The rings and clam are thenwithdrawn from the sleeve and the outer peripheral surfaces of the ringsare ground to correct size.

One embodiment of the invention has been illustrated in the accompanyingdrawings, in which:

Fig.` l illustrates the method of contracting the ring;

Fig. 2 illustrates the contracted ring with the retaining member inposition around the ring;

Fig. 3 is a perspective view of a portion of the contracted ring showingthe soldered ends of the retaining band illustrated in Fig. 2;

Fig. 4l illustrates in longitudinal section the prepared sleeve with thearbor and rings positioned therein, and

Fig. 5 illustrates in longitudinal section a plurality yof clamped ringsready to be ground.

The first step in my improved process of manufacturing piston rings isillustrated in Fig. 1, wherein a piston ring l() is surrounded by aflexible wire 1l, the free ends of the wire being twisted together asshown at l1 by any suitable means until the split between the ends ofthe ring is closed. Since the ring is contracted by means of a flexiblemember the ring is not distorted in any way and, therefore, will assumeits natural shape if allowed again to expand.

After the ring has been so contracted, it may be inserted in a clamp andground to size after the flexible member or band has been removed, butit is probable that, for economical reasons, a manufacturer would desireto finish a plurality of rings at the saine time and ill QlClGl" thatthis may b9 done the contracted ring is encircled by a flexible bandsuch as a copper band 12, illustrated in Fig. 2, the ends of the bandbeing connected together, as by solder 13, to retain the ring incontracted position. This ring is then used as a pattern or templet anda sleeve is prepared, the inner surface of the sleeve corresponding insize and shape to the outer peripheral surface of the contracted ring.Such a prepared sleeveis il lustrated at 14 in Fig. 4 and a plurality ofrings 1() is inserted in the cylinder With their split portions insubstantial alignment and disposed in the same relative position as thesplit portion of the original pattern ring. It is important that therings inserted in the cylinder be as nearly homogeneous as possible Withthe ring first contracted, for otherwise the rings would not becontracted Without distortion.

After the rings have been inserted in the sleeve an arbor 15 is insertedin the sleeve, this arbor being provided With an annular iange 16positioned adjacent one end thereof and an adjustable collar 17 adjacentthe opposite end thereof. The sleeve 14 with the rings 1() positionedtherein is properly centered' on, the arbor. 15,A this centering beingaccomplished on a suitable device, such as al. lathe in order to, insurea uniform amount of material being ground from the outer surfaces of therings. i After this centering has been accomplished, the sleeve isprovided with annular cut-away portions or recesses 18 for the,reception of collars 19 which are positioned between the members 16 Vand17 and the sleeve and. center the sleeve onv the arbor. A nut 2()engages a screw threaded portion 21 on the arbor and clamps the vcolla-r17 against the outer piston ring, thereby retaining the rings inposition between the collar 17 and the flange 1G. The arbor or clamp andthe piston rings are then Withdrawn from the sleeve 141-A and the outerperipheral surfaces ofthe rings are ground to correct size. l

By carrying out the above described process of manufacturing pistonrings, it will be evident that the rings produced will be free fromdistortion and Will expand evenly and will have true cylindrical outerperipheral surfaces.

`While one embodiment of the invention has been illustrated anddescribed, it should be understood that the invention is capable ofmodilication and that modifications and changes may be made Withoutdeparting from the spirit or scope of the invention, as expressed in thefollowing claims.

I'hat I claim and desire to secure by Letters Patent is:y

1.V In an apparatus for producing piston rings, a sleeve for holding therings preliminary to clamping, the inner contour of said sleeveCorresponding in size and shape to the contracted ring, said sleevehaving an annular recess at one end, and clamping means having acentering device cooperating With Vsaid recess.

2.A In an apparatus for producing pistonV rings, a sleeve for holdingthe rings preliminary to clamping, theV inner contour ofl said sleevecorresponding in size and shape tothe contracted ring, said sleevehaving annularv recesses at its ends, and centering rings for the clamparranged' in said recesses.

3. In an apparatus for producing piston rings, a sleeve for holding therings preliminary to clamping and grinding, the inner contour of saidsleeve corresponding in sizeV and shape to the outer periphery of a ringwhich hasl been contracted Without distortion. i i

4f. In an apparatus for producing piston rings, a sleeve for holding.the rings preliminary to clamping and grinding, the inner contour ofsaid sleeve corresponding in size andv shape to the outer periphery of aring; which has .been contracted by means of a flexible band.

In testimony whereof I atlix my signature.

EDIVARD; H. WEHLANN,

